The distribution and ontogenic variations in the five alkaloids previously isolated fromNarcissus assoanusDuf. (pseudolycorine, two new acetylated derivatives: I‐O‐acetylpseudolycorine and 2‐O‐acetylpseudolycorine, and two phenanthridines: assoanine and oxoassoanine) were studied. The alkaloids have been separated and quantified by high performance liquid chromatography, and the free amino acids phenylalanine and tyrosine were also analyzed. Comparing the results obtained for aerial parts and bulbs, we suggest that alkaloids are synthesized in the aerial part of the plant, and propose a likely biosynthetic